(USA Today) - Are you wondering whether Robert Griffin III can return by next season, and if the Washington Redskins quarterback will ever be able to recapture his eye-popping form after reconstruction surgery on his right knee?

Don't worry says his father, who on Friday told USA TODAY Sports that his son is already feeling better than he did a few days after his 2009 anterior cruciate ligament reconstruction surgery.

Robert Griffin II said his son will try to match the remarkable comeback of Minnesota Vikings running back Adrian Peterson, who returned from a torn ACL suffered on Dec. 24, 2011, to lead the NFL in rushing and nearly break the single-season rushing record.

"Watch! I'm optimistic,'' Griffin II said in a phone interview. "He's doing really good. No problems. Everything seems to be working out pretty good. It's not as bad as everybody thinks. He's determined and motivated to be back.

"Time-wise, he has enough time ahead of him. Eight months is a lot of time. After eight months last time (in 2009), he felt very good, and the people around him felt very good."

He added: "And when he sees his coaches and everyone else, it's going to be like nothing ever happened."

Barring any unforseen setback, Griffin II expects his son to be back -- good as ever -- for the 2013 season opener in September. He said everything went well during the ACL and lateral collateral ligament repair performed Wednesday by renowned orthopedic surgeon James Andrews. Griffin II said the ACL tore only partially, which he considers great news.

But, everyone wants to know: Will RGIII ever be RGIII again?

"You saw Adrian Peterson, what he went through, and it was the same doctor,'' RGII said. "And Peterson was a running back. Robert will have to do everything that this guy did in his comeback.''

Peterson made it back to start the Vikings' 2012 season opener and rushed for 2,097 yards after shredding his ACL on Christmas Eve. Griffin II said Peterson is RGIII's rehabilitation role model and motivation.

"We know what it takes,'' he said. "We know an uphill battle for (Griffin III) is not much. It's a matter of letting his body do its work. He's a little older, a little stronger. He's looking really good.''

Griffin's dad said six months will be a key checkpoint to "see how his body reacts.''

"Based on last time, where he actually was within six months, we're optimistic,'' RGII said. "The LCL has to heal. But what they're doing with advancements in medicine, his LCL is going to be 100%, He's going to be really, really in great shape.

"He didn't (completely) tear his ACL, which is perfect. Because when you do that, you lose a lot of muscle mass in your upper thigh. But he was able to fire his muscles up early on in rehabilitation. In his case, everything is going really well. It's early. But trust me, he even acknowledged the difference between the first time and this time, as far as that first week.''

Griffin II said the timetable for his son's rehabilitation is not being rushed.

"But in about another two months, you guys are going to be saying, 'Oh, my goodness,''' Griffin said. "The first full month is critical. Everything is going really good."

Griffin III remains at the Andrew Institute in Pensacola, Fla., where he had the four-hour surgery that included a patellar graft reconstruction, his father said. He already has begun his rehabilitation at the facility.

"The last time at the five-month mark, everybody was looking at him like, 'Wow!'' RGII said. "And then, every milestone after that is great. We are very, very optimistic about Robert's health.''

RGII acknowledged that his son's take-off-and-run playing style will have to change and that he's willing to make those changes to prolong his career. Griffin II added that the Redskins probably have already started making changes in the playbook.

"Robert didn't have a high passer rating just from running the football,'' RGII said. "That's something that the organization and Robert really need to address. With his health, his longevity, that's probably already started. We'll see. I know that he is taking in everything that was told to him. He's definitely going to protect himself.''

Griffin has already set rehabilitation goals with his dad.

"We already made plans for milestones,'' RGII said. "He's a quarterback. We're taking everything into consideration and we're going to make sure that arm stays lively. That's the plan that we have.''